fix: harden queue retries and quota reservation

src/api/admin.rs

@@ -1585,10 +1585,10 @@ async fn test_mail(
 
 fn mask_secret(secret: &str) -> String {
     let trimmed = secret.trim();
-    if trimmed.len() <= 8 {
+    if trimmed.chars().count() <= 8 {
         return trimmed.to_string();
     }
-    format!("{}...", &trimmed[..8])
+    format!("{}...", trimmed.chars().take(8).collect::<String>())
 }
 
 #[derive(Debug, FromRow, Serialize)]
@@ -1678,3 +1678,15 @@ async fn update_config(
         data: row,
     }))
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn secret_masking_never_splits_utf8() {
+        assert_eq!(mask_secret("12345678abcdef"), "12345678...");
+        assert_eq!(mask_secret("中文密钥测试内容"), "中文密钥测试内容");
+        assert_eq!(mask_secret("🔑🔑🔑🔑🔑🔑🔑🔑more"), "🔑🔑🔑🔑🔑🔑🔑🔑...");
+    }
+}